USGS 02299727 SHAKETT CREEK NEAR NOKOMIS FL

Data are tidally affected -- Astronomical tides cause
significant cycles of approximately 24.84 hours at this site.
Because a different portion of the 24.84-hour tidal cycle is
averaged in successive daily (24-hour) computations, a systematic
secondary oscillation, unrelated to basin hydrology and having a
period of about two weeks may be apparent in daily data.